You don't need it but gore Tex is rad for the PNW. Medium insulation at most on both pants and jacket. Like these guys said, keep it light under your jacket or you'll soak from the inside. At least 10k breathability is a must because you'll probably be working harder than climates with lighter snow.
Much of the season is socked in with fog and flat light so get yourself some lenses that let in a lot of light. Make time to get to baker.